Rhododendron plant named `WALPINRUF&#39;

ABSTRACT

A new and distinct variety of  Rhododendron  plant named ‘WALPINRUF’ which is characterized by a compact mounding habit, glossy evergreen foliage, large double flowers in a warm pink color, which are produced from spring until early summer, is disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. 119 ofU.S. Provisional Application No. 61/956,956 filed on Apr. 20, 2013entitled Rhododendron plant named ‘WALAZ03’ and for which the inventornow wishes to file this application with the cultivar name ordenomination ‘WALPINRUF’.

GENUS AND SPECIES

Rhododendron kaempferi hybrid

VARIETY DENOMINATION

‘WALPINRUF’

BACKGROUND OF THE NEW PLANT

The present invention relates to a new and distinct cultivar ofRhododendron, also commonly known as evergreen azalea, which is grown asan ornamental shrub for use in planted containers and in the garden andlandscape. The new cultivar is known botanically as Rhododendronkaempferi hybrid, and will be referred to hereinafter by the cultivarname ‘WALPINRUF’.

‘WALPINRUF’ arose and was selected from a long term breeding programcommenced in 1993 or 1994. The aim of the breeding program was todevelop one or more matched series of novel cultivars of hardy evergreenazaleas with showy flowers. Breeding commenced with Azalea ‘Elsie Lee’as one of the initial parents. Azalea ‘Elsie Lee’ is a Shammarellohybrid, raised in Ohio in the 1960s and renowned for its relativehardiness among evergreen azaleas. Although several Shammarello hybridswere patented in the 1960s and 1970s, Azalea ‘Elsie Lee’ is believed tobe unpatented. ‘Elise Lee’ bears light mauve-blue semi-double flowers.

Commencing in 1993 or 1994, many generations of deliberate hybrids wereraised, selecting promising parents from previous unnamed seedlingswhich had been raised during the breeding program. ‘WALPINRUF’ wasselected in 2003 or 2004. The parents of ‘WALPINRUF’ are unknown andhave not been retained: no parental comparison information is available.

Asexual propagation of ‘WALPINRUF’ was first accomplished in 2003 or2004 using semi-ripe shoot cuttings. Since that time, under carefulobservation, the distinguishing characteristics of ‘WALPINRUF’ have beendetermined stable and uniform, and to reproduce true to type insuccessive generations of asexual propagation.

SUMMARY

The distinguishing characteristics of ‘WALPINRUF’ are as follows:‘WALPINRUF’ has not been tested under all possible conditions andphenotypic differences may be observed with variations in environmental,climatic, and cultural conditions.

1. Plants of ‘WALPINRUF’ exhibit a compact mounding growth habit.

2. The foliage of ‘WALPINRUF’ is glossy evergreen in color.

3. ‘WALPINRUF’ bears large double flowers in a warm pink color.

4. Plants of ‘WALPINRUF’ show good heat and humidity tolerance.

5. ‘WALPINRUF’ blooms from late spring through early summer.

6. After two years of growth, plants of ‘WALPINRUF’ are 25 cm to 30 cmin height and 25 cm to 30 cm in width.

7. At maturity, 5 years, plants of ‘WALPINRUF’ are 30 cm to 40 cm inheight and 30 cm to 40 cm in width.

8. ‘WALPINRUF’ prefers semi-shade in a moist, well drained, slightlyacidic growing media.

9. ‘WALPINRUF’ is suitable for use as a garden specimen, landscapeplants and as a container specimen.

10. ‘WALPINRUF’ is hardy to at least USDA Zone 7.

COMPARISON WITH KNOWN VARIETIES

‘WALPINRUF’ may be compared with the following two varieties of azalea:Azalea ‘Roblec’ (U.S. Plant Pat. No. 15,339) and Azalea ‘Roblea’ (U.S.Plant Pat. No. 12,142). Whereas ‘WALPINRUF’, ‘Roblec’ and ‘Roblea’ allbear semi-double pink flowers, the comparison varieties ‘Roblec’ and‘Roblea’ were developed and selected for their ability to rebloom inlate summer and fall. ‘WALPINRUF’ blooms only in the late spring throughearly summer and does not rebloom.

‘WALPINRUF’ may also be compared with Azalea ‘YBAZ-2504’ (U.S. PlantPat. No. 21,475). Whereas ‘WALPINRUF’ and ‘YBAZ-2504’ bear semi-doublepink flowers, the comparison variety ‘YBAZ-2504’ is a florist orgreenhouse variety which is not hardy. ‘WALPINRUF’ has been observed totolerate temperatures as low as −15° C. (USDA Hardiness Zone 7).

DESCRIPTION OF THE PHOTOGRAPHS

The accompanying color photographs illustrate the overall appearance of‘WALPINRUF’ showing the colors of its foliage and flowers as true as itis reasonably possible to obtain in colored reproductions of this type.Both photographs have been made from two year old plants which have beengrown out of doors in Sacramento, Calif.

FIG. 1 shows an entire or whole plant of ‘WALPINRUF’.

FIG. 2 depicts a close-up view of the flowers of ‘WALPINRUF’.

BOTANICAL DESCRIPTION OF THE PLANT

The following is a detailed description of ‘WALPINRUF’. The observedplant was 2 years old growing outdoors in a 1-gallon container in SantaBarbara, Calif. Observations, measurements, values and comparisons werecollected in April of 2014 where the botanical description was made. Thecolor determinations are in accordance with the 2007 edition of theColour Chart of The Royal Horticultural Society, London, England, exceptwhere general color terms of ordinary dictionary significance are used.Growing conditions are similar to those of other Rhododendron.

-   Botanical classification:    -   -   Genus.—Rhododendron.        -   Species.—kaempferi hybrid.        -   Cultivar.—‘WALPINRUF’.        -   Commercial classification.—Perennial.        -   Common name.—Evergreen Azalea.-   Parentage: Unnamed seedlings raised during the breeding program.    Parents not retained or described.-   Propagation method: Semi-ripe cuttings without use of rooting    hormone.-   Plant description:    -   -   Use.—Ornamental for container or landscape.        -   Cultural requirements.—Plant in partial shade and any            free-draining slightly acidic soil.        -   Particular pest resistance or susceptibility.—None observed.        -   Rooting system.—Fine and fibrous.        -   Vigor.—Moderately vigorous. Lateral branching is encouraged            by pinching.        -   Habit.—Inverted cone.        -   Dimensions after two years.—25 cm to 30 cm in height and 25            cm to 30 cm in width.        -   Dimensions after five years.—30 cm to 40 cm in height and 30            cm to 40 cm in width.        -   Hardiness.—USDA Zone 7.-   Stem:    -   -   Dimensions.—Length 1.5 cm (height of manual pinch). Diameter            at base: 1 cm.        -   Shape.—Cylindrical.        -   Bark.—Rough, color 172A.        -   Number of branches.—12.-   Branches (current season extension growth):    -   -   Shape.—Cylindrical.        -   Dimensions.—Length: 18 cm to 25 cm, diameter 3 mm to 4 mm.        -   Color.—N144A.        -   Internode length (range).—1 cm to 2 cm.-   Branches (previous year's growth):    -   -   Shape.—Cylindrical.        -   Dimensions.—Length: 20 cm to 25 cm, diameter 3 mm to 4 mm.        -   Color.—172A.        -   Bark surface.—Rough.        -   Internode length (range).—1 cm to 2 cm.-   Foliage:    -   -   Type.—Evergreen.        -   Leaf arrangement.—Alternate.        -   Leaf division.—Simple.        -   Leaf dimensions (average, fully developed).—5 cm in length            and 3 cm in width.        -   Leaf color (current season new growth, adaxial            surface).—144A.        -   Leaf color (current season new growth, abaxial            surface).—144A.        -   Leaf color (mature, previous year's growth, adaxial            surface).—147A.        -   Leaf color (mature, previous year's growth, abaxial            surface).—138A.        -   Leaf shape.—Elliptic, base cuneate, apex obtuse.        -   Leaf margin.—Ciliate, hairs fine, 1 mm to 2 mm, silver-gray            156D.        -   Leaf surface (both surfaces).—Smooth, glossy, pubescent,            hairs fine, 1 mm to 2 mm, silver-gray 156D.        -   Venation.—Pinnate, color 144A.        -   Petioles.—Dimensions: 5 mm in length, 1.5 mm in width.            Color: N144A.-   Inflorescence:    -   -   Inflorescence type.—Terminal.        -   Flower arrangement.—Flowers in groups of 8 to 10.        -   Flower aspect.—Upward or outward.        -   Form.—Rotate.        -   Inflorescence quantity.—Ranges between 3 and 5 per branch            and between 30 and 50 at peak of flowering.        -   Dimensions of inflorescence (average).—10 cm in diameter, 8            cm in depth.        -   Blooming season.—Spring.        -   Lastingness of flowers (on the plant).—7 to 10 days.-   Bud:    -   -   Arrangement.—Borne in clusters of 8 to 10 buds. Initially,            each bud is sheathed by a pair of modified leaf bracts which            fall away as the bud swells.        -   Bud shape.—Ovoid.        -   Dimensions (immediately prior to opening).—18 mm in length            and 12 mm in diameter.        -   Bracts (bud sheath).—Pair, each 15 mm in length and 10 mm in            width.        -   Bracts (bud sheath).—Shape cupped, texture paper-like, base            truncate, apex acute.        -   Bract color (both surfaces).—167C.        -   Bud color (as bracts fall away, as bud opens).—39B.        -   Sepals.—5 in number, fused at base.        -   Sepal color (adaxial surface).—191B, surface pubescent,            hairs fine, 1 to 2 mm, silver-gray 156D.        -   Sepal color (abaxial surface).—137B, surface smooth.        -   Sepal dimensions.—Length: 8 mm; width: 6 mm.        -   Sepal shape.—Ovate, base rounded, apex cuspidate.        -   Sepal surface.—Pubescent, many fine hairs 1 mm to 2 mm,            silver-gray 156D.        -   Pedicel.—Length 18 mm, width 1.5 mm.        -   Pedicel surface.—Pubescent, many fine hairs 1 mm to 2 mm,            color 191B.-   Flowers (petals and petaloids):    -   -   Form.—Semi-double.        -   Flower dimensions.—6 cm in diameter, 2.5 cm to 3.0 cm in            depth.        -   Petal arrangement.—Three whorls, each whorl consisting of 5            petals fused at base.        -   Petal shape.—Widely ovate, base truncate, apex rounded.        -   Petal dimensions.—Outer whorl: 35 mm in length, 30 mm in            width. Second whorl: 32 mm in length, 25 mm in width. Inner            whorl: 26 mm in length, 22 mm in width.        -   Petal margin.—Smooth, gently ruffled.        -   Petaloids.—Occasionally present, approximately 2 to 3 per            flower. Shape: Subulate, irregular. Dimensions: 12 mm in            length, 2 mm to 7 mm in width.        -   Petals and petaloids.—Color (both surfaces): Opening N66B            becoming N66C when fully developed. Spots: Occasionally            present as short dashes towards petal base, length 1 mm to 2            mm, width 0.5 mm to 1.0 mm, color red-purple 61B. Surface:            Smooth, glossy.        -   Venation.—Parallel, color N66B.        -   Peduncle.—Dimensions: 5 mm in length, 2 mm in width, ribbed.            Surface: Smooth. Color: 144D.-   Reproductive organs:    -   -   Stamens, anthers.—Absent.        -   Pistil.—Length 5 mm, diameter 0.5 mm, color 13C.        -   Stigma.—Color 137B.        -   Ovary.—Ovate, 4 mm in length, 3 mm in diameter. Surrounded            by dense very fine silver-gray hairs, nearest 156D.

I claim:
 1. A new and distinct cultivar of Rhododendron plant named‘WALPINRUF’ as described and illustrated herein.